Effect of different disaccharides as energy supplements in tris-egg yolk semen extender on the quality of cryopreserved boer goat spermatozoa

Abstract

The quality of cryopreserved Boer goat semen may be influenced by the source and concentration of energy supplements in the extender. The aim of the study was to improve the protocols for cryopreservation of Boer goat spermatozoa using different disaccharides concentrations as supplements in tris- egg yolk extender. Two experiments were carried out to investigate the effect of (a) addition of three disaccharides (maltose, sucrose and trehalose) and (b) disaccharides combination (maltose and trehalose) at different concentrations using tris-egg yolk extender. For experiment 1: the study was replicated six times and was conducted in a 3 x 2 x 2 factorial arrangement with three different sugars (sugars: maltose, sucrose and trehalose), two sugar concentrations (0.12g and 0.22g) and two evaluation times (0 hours before cryopreservation and 120 hours after cryopreservation). For experiment 2: the study was replicated six times and was conducted in a 2 x 2 factorial arrangement with two sugar concentrations (0.12g and 0.22g) and two evaluation times (0 hours before cryopreservation and 120 hours after cryopreservation). Semen ejaculates were collected at 7.00-9.00 am from three Boer goats twice per week. After collection, the semen samples were pooled and diluted with tris-egg yolk extender at the ratio of 1:7 (semen to extender). Sperm quality (progressive motility, non- progressive motility, kinetic motions, viability (live/dead) and morphology) were analyzed using computer aided sperm analyzer (CASA). For experiment 1: sucrose 0.12g had higher progressive motility (PM %) when compared to maltose, and trehalose at 0h but reduced after cryopreservation. Sucrose 0.12 showed high percentage of kinetic motions (straightness and average path velocity) when compared to other sugars at 0 hours. More morphological defects M (CH) were revealed by maltose 0.12 at 0 hours. Sugar type (ST) and evaluation time (ET) showed no significant difference (P>0.05) in progressive motility (PM %), sperm kinetic motion, sperm viability and morphology. For experiment 2: mixed/combined 0.12g (maltose and trehalose) revealed more progressive motility (PM %) at 0h and reduced after cryopreservation. Table 6 and 9: of experiment 1 and 2 showed an interaction caused by sugar concentration level and evaluation time (L X ET) on the percentage of cut head M (CH%) and coiled M(C%) morphological abnormalities. In conclusion addition of maltose 0.12g to the extender showed almost similar results with that of trehalose at 0h and 120h. Therefore addition of maltose and trehalose to the extender might improve the quality of Boer goat spermatozoa prior and post cryopreservation.